Acta Scientiarum http://periodicos.uem.br/ojs/acta ISSN on-line: 1807-863X Doi: 10.4025/actascibiolsci.v41i1.46666 ZOOLOGY Length-weight relationship and condition factor of eight fish species from the upper Araguari River, State of Amapá, Brazil Luiza Prestes1,2*, Marcos Sidney Brito Oliveira3,4, Marcos Tavares-Dias3,4, Maria Gercilia Mota Soares5 5 and Fabiana Calacina da Cunha 1Programa de Pós-Graduação em Ecologia Aquática e Pesca, Universidade Federal do Pará, Avenida Presidente Tancredo Neves, 2501, 66077-830, Belém, Pará, Brazil. 2Programa de Graduação em Engenharia de Pesca, Universidade do Estado do Amapá, Avenida Presidente Vargas, 100, 66077-830, Macapá, Amapá, Brazil. 3Programa de Pós-Graduação em Biodiversidade Tropical, Universidade Federal do Amapá, Macapá, Amapá, Brazil. 4Empresa Brasileira de Pesquisa Agropecuária, Macapá, Amapá, Brazil. 5Instituto Nacional de Pesquisas da Amazônia, Manaus, Amazonas, Brazil. *Author for correspondence. E-mail:
[email protected] ABSTRACT. The present study estimated parameters of the length-weight relationship (LWR) and allometric condition factor for eight fish species from the upper Araguari River, in the State of Amapá, Brazil. A total of 615 fish of eight species were analyzed: Acestrorhynchus falcatus, A. falcirostris, Ageneiosus inermis, Hemiodus unimaculatus, Hoplias aimara, Myloplus asterias, M. ternetzi and Tometes trilobatus. The allometric condition factor varied from 0.742 to 1.435. The coefficient of allometry ranged from 2.723 to 3.225. The coefficient of determination (R2) of the LWR ranged from 0.742 to 0.985. This is the first estimate of the length-weight relationship for fish from the Araguari River and the first record of these parameters for Myloplus ternetzi and Tometes trilobatus.